The present invention relates generally to multi-stage rockets, missiles and the like. More particularly the present invention is related to a system wherein a single propulsion system may be sequentially operationally employed in conjunction with a plurality of separate, intercommunicating, axially aligned stages.
Rockets have long been separated into multiple, substantially independent stages so that unnecessary mass may be periodically ejected during flight. Usually each independent stage comprises an independent propulsion system and an associated propellant supply. When the propellant in one stage has been consumed, this stage is jettisoned, and the next stage then ignites or fires using its own propulsion. This method allows the performance of the vehicle to be increased, for the excess mass of expended stages does not have to be carried during the remainder of the rocket's powered flight. Yet attempts to increase the rocket's performance even more by dividing it into a greater number of stages have failed because the mass of independent motors in each stage defeats the purpose of increasing the number of stages.
Other systems of staging have been proposed. U.S. Pat. No. 3,067,575 describes a rocket in which the motor rises up into the propellant tank as the propellant is consumed and melts the tank walls beneath it. However, this system requires seldom-used gel propellant. Additionally, it must pull the rocket motor upward with a separate hydraulic motor. Moreover, the latter system expends part of its thrust to melt the vessel walls, and it is susceptible to numerous difficulties associated with uniform and controlled consumption of the walls. Bono's vehicle, pictured in U.S. Pat. No. Des. 201,773, systematically empties and jettisons several propellant tanks strapped on a central motor-bearing core, according to Philip Bono and Kenneth Gatland, Frontiers of Space, The Macmillan Company, New York, 1969. But this rocket suffers from large mass and aerodynamic penalties and makes no provision for discarding the tanks inside the core.
Further attention is directed to the following U.S. Pat. Nos. 2,835,199; 2,988,879; 3,023,573; 3,032,979; 3,046,736; 3,067,574; 3,070,565; 3,122,884; 3,138,929; 3,154,041; 3,304,724.